Ligand uptake is relatively unaffected in LRBA-deficient patients. (A) CD4 T cells were stimulated with CD3/CD28 beads and total CTLA-4 (C19) plotted against CD80-Ig uptake gating on CD4⁺ memory Tregs. Slope of the line represents efficiency of CD80 uptake. Dotted lines are overlaid in the control plot (top left) for comparison. CTLA-4-Ig treatment (bottom panels) provides a negative control by blocking ligand uptake. CD80-Ig MFI is shown in large font (top right) and CTLA-4 MFI in large font (bottom right). Percentages are shown in all quadrants. (B) Graph is generated using the slope of the line of best fit from the data in panel A. (C) Collated ligand uptake efficiency data are shown for CTLA-4 and LRBA mutations.